Slurry hydrocracking methods involve the processing of a heavy feed stock, such as vacuum residues, and fine particulate catalyst in an upflow reactor in a hydrogen-rich environment. This reaction environment facilitates the very high conversion of the heavy feed stock to liquid products, particularly distillate boiling-range components.
A typical slurry hydrocracking method includes introducing a heated heavy feed stock into a slurry hydrocracking (SHC) reactor. An effluent from the SHC reactor is directed to a separation zone (which may include, e.g., vacuum distillation) for recovery of light ends, naphtha, diesel range distillate, vacuum gas oils and unconverted heavy feed (pitch).
Conventional slurry hydrocracking methods, however, present several challenges. For instance, toluene insoluble material can accumulate in the SHC reactor leading to increased coking. Further, an amount of unconverted pitch and vacuum gas oils may leave the SHC reactor before being converted into more desirable components. That is, a portion of the effluent leaving the slurry reactor typically includes an amount of unconverted pitch (that may have a boiling point greater than about 975° C.) and vacuum gas oil that may be as much as 1-3% of the feed.
Accordingly, it is desirable to provide methods and systems that allow for reducing toluene insoluble material, and in particular mesophase materials, in the SHC reactor. In addition, it is desirable to provide methods and systems that reduce feed bypass. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and appended claims, taken in conjunction with the accompanying drawings and this background of the invention.